Although perioperative β-blocker therapy initiated within hours before surgery has been reported to reduce the frequency of myocardial infarction and in-hospital mortality, it has been associated with a greater risk of acute stroke and all-cause mortality. The hypothesis that neither initiation of β-blocker therapy within 60 days of surgery nor chronic β-blocker dispensing (more than 60 days before surgery) would be associated with a higher risk of stroke was tested using data from 204,981 insured individuals who underwent major abdominal surgery between 2005 and 2015. The frequency of perioperative stroke in β-blocker–naïve patients was 0.2% (235 of 155,531). The frequency of stroke in patients with preoperative β-blocker therapy initiated within 60 days of surgery was 0.4% (17 of 4,026) and that in patients on a chronic β-blocker therapy was 0.4% (171 of 45,424). After propensity score weighting, patients begun on a β-blocker therapy within 60 days of surgery (odds ratio, 0.90; 95% CI, 0.31 to 2.04) or on chronic β-blocker therapy (odds ratio, 0.86; 95% CI, 0.65 to 1.15) had a stroke risk similar to that in β-blocker–naïve patients. See the accompanying Editorial on page 7.The theory that supplemental intraoperative oxygen might reduce postoperative nausea and vomiting is based on the hypothesis that inadequate oxygen supply to gastrointestinal tissues triggers release of serotonin from local vagal afferent nerve terminals, which might then activate emetic brain centers. The hypothesis that supplemental intraoperative oxygen (80% fraction of inspired oxygen [Fio2]) reduces the incidence of postoperative nausea and vomiting compared to 30% Fio2 in adults who had major abdominal surgery was tested in a post hoc subanalysis of a cluster-crossover trial that included 5,057 colorectal surgeries. The incidence of postoperative nausea and vomiting was 852 of 2,554 (33%) surgeries assigned to 80% oxygen and 814 of 2,503 (33%) surgeries assigned to 30% oxygen, for a relative risk (95% CI) of 1.04 (0.96 to 1.12). A meta-analysis of 10 trials, including the present results, representing 6,749 patients showed little evidence of a benefit of perioperative administration of supplemental oxygen (80%) on the prevention of postoperative nausea and vomiting compared to routine inspired oxygen (30%); the relative risk (95% CI) was 0.97 (0.86 to 1.08). See the accompanying Editorial on page 10.Phantom limb pain is thought to be at least partially sustained by abnormal input from the peripheral to the central nervous system. Cryoneurolysis provides a prolonged neural block by application of very low temperatures to reversibly ablate peripheral nerves. The hypothesis that the change in average phantom limb pain intensity at 4 months after ultrasound-guided percutaneous cryoneurolysis would be more than after sham treatment was tested in a randomized, sham-controlled study of 144 patients with established lower-extremity phantom limb pain resulting from an amputation. Each patient received a single-injection femoral and sciatic nerve block with lidocaine before being randomized to receive either cryoneurolysis or sham treatment. Pretreatment phantom pain scores were a median [interquartile range] of 5 [4 to 6] for active treatment (cryoneurolysis) and 5 [4 to 7] for sham treatment. At 4 months, average phantom limb pain scores were 4.3 [1.5 to 6] for active treatment and 4.5 [2 to 6] for sham treatment, with an estimated difference in means (95% CI) of –0.1 (–1.0 to 0.7).Postoperative pain associated with living donor open partial hepatectomy can be intense and persistent. Intraoperative IV lidocaine infusions in patients undergoing open abdominal procedures reduce both postoperative pain scores and morphine requirements in the first 72 postoperative hours. Lidocaine undergoes hepatic metabolism to the active metabolites monoethylglycinexylidide and glycinexylidide, which also undergo hepatic metabolism. Pharmacokinetic changes experienced by patients undergoing living donor hepatectomy are likely due to the anesthesia, laparotomy, and isolation of hepatic blood vessels for liver resection. The hypothesis that the elimination clearances of lidocaine, monoethylglycinexylidide, and glycinexylidide are reduced after a partial hepatectomy for living liver donation was tested in 15 patients who received intraoperative IV lidocaine infusions until graft isolation. The typical value (± standard error of the estimate) for baseline lidocaine elimination clearance, 0.55 ± 0.12 l/min, decreased to 0.17 ± 0.02 l/min once the donor graft was surgically isolated and monoethylglycinexylidide and glycinexylidide clearances were proportionately reduced after hepatectomy. The fraction of the liver remaining was a significant model covariate.Anaphylaxis is the most severe form of immediate hypersensitivity reaction, due to the massive release of multiple physiologically active mediators by inflammatory cells. Perioperative anaphylaxis is a rare complication of anesthesia but can be associated with major morbidity and mortality. Although its diagnosis can be difficult in intubated and unconscious patients, it usually presents as acute cardiopulmonary dysfunction with changes in oxygen saturation or acute hemodynamic instability ranging from varying degrees of hypotension to complete cardiac arrest. Prompt recognition of the reaction and immediate cardiopulmonary resuscitation with intravenous epinephrine are important for initial management. Volume administration is required due to the profound hypovolemia that can occur during perioperative anaphylaxis. The decision to proceed with surgery after anaphylaxis should be individualized depending on the severity of the reaction, cardiopulmonary stability, and the urgency of the procedural intervention. If perioperative anaphylaxis is suspected, the patient should be referred to an allergist to identify the responsible agent and provide guidance for future anesthetics.Practice guidelines are systematically developed recommendations that aim to improve patient care and patient outcomes by providing up-to-date information for patient care. The 2023 American Society of Anesthesiologists Practice Guidelines for Monitoring and Antagonism of Neuromuscular Blockade provide evidence-based recommendations focusing primarily on the type and site of monitoring and the process of antagonizing neuromuscular blockade to reduce residual neuromuscular blockade. These guidelines recommend using quantitative neuromuscular monitoring at the adductor pollicis muscle and confirming recovery of train-of-four ratio greater than or equal to 0.9 prior to extubation. Sugammadex is recommended for reversal of deep, moderate, and shallow levels of neuromuscular blockade that is induced by rocuronium or vecuronium. Neostigmine is suggested to be a reasonable alternative to sugammadex for antagonism of minimal neuromuscular blockade (train-of-four ratio in the range 0.4 to less than 0.9). Patients with spontaneous recovery to train-of-four ratio greater than or equal to 0.9 identified with quantitative neuromuscular monitoring do not require pharmacologic antagonism. Methods for implementing routine quantitative monitoring for patients receiving neuromuscular blocking agents are discussed. See the accompanying Editorial on page 4.
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Mar 28, 2024
Peng-Fei Gao + 6